7 December 2011

DENSO Corporation has jointly developed a home energy management system (HEMS) with Toyota Housing Corporation and Misawa Homes Co., Ltd. The HEMS, DENSO’s first such product of its kind, has optional functions that work with plug-in hybrid (PHEV) or electric (EV) vehicles. It will be available in the Japanese market in or after February 2012.

As plug-in hybrid and electric vehicles become more widespread, we recognized that it’s possible to realize a more environmentally friendly society by connecting and coordinating these types of vehicles and home energy usage. DENSO will not only contribute to the development of environmentally friendly vehicles, but also to the development of products that help improve home energy efficiency.

—Koji Kobayashi, executive vice president of DENSO Corporation

DENSO HEMS. Click to enlarge.

DENSO’s HEMS consists of a control unit and a 7-inch touch panel monitor, installed inside the house. The monitor shows real-time power consumption, helping to remind users to turn off appliances when they are not in use, which also helps them better manage electricity. The monitor can also show electricity consumption in terms of cost and the amount of CO2 emissions that are emitted, as well as historical data, which helps encourage users to be more aware of saving energy. Additionally, the system prevents the circuit breaker from tripping when there is a high electric load.

When the HEMS is connected to an external information center it allows the user to remotely check and switch on and off some home appliances from his or her smartphone. For example, users could switch on climate control systems, check whether the electrically controlled front door is properly locked, and fill the bathtub with hot water using the smartphone.

Consumers also can use HEMS to schedule a time to charge a plug-in hybrid or electric vehicle battery by coordinating with vehicle battery chargers. Consumers can schedule battery charging for nighttime, when electricity rates are lower. After signing a contract with a carmaker and connecting with the information center, users can remotely turn on the vehicle’s climate control system using the HEMS monitor or smartphone.

DENSO has also jointly developed a household storage battery system with Toyota Housing Corporation, Misawa Homes Co., and Shin-Kobe Electric Machinery Co., Ltd. When used with the HEMS, the battery, with a capacity of 8.4 kWh, can better control power consumption at home during peak demand hours. The battery system can power a minimum number of appliances, such as room lighting, for a certain period of time in case of a power outrage.

These products utilize the results from the Japan’s Ministry of Economy, Trade and Industry’s “Next-Generation Energy and Social Systems Demonstration” (5 year plan from 2010). DENSO will continue to improve these products with input from this project.

Comments

This could be very appropriate with future decentralized (solar) energy generation systems and electrified vehicles. The BEV large battery pack could be used to store solar energy during daytime and to recharge the second BEV when at home.

At this point in time a home battery can make sense in two situations:
1. As a backup system if you suffer frequent grid failures
2. If you have solar panels and the energy company doesn't offer net metering

For the forseeable future, the grid will be dominated by fossil fuel generation. Solar power that you feed into the grid will show up on the TSO's radar as reduced consumption and they will simply dial back their fossil and or hydro plants.